1. Field of the Invention
Aspects of the present invention relate to an organic light emitting diode, and more particularly, to an organic light emitting diode that can improve a driving voltage and emission efficiency and an organic light emitting display having the same.
2. Description of the Related Art
An organic light emitting display is a self-emitting display using a phenomenon in which electrons and holes injected into an organic material through an anode and a cathode are recombined to form excitons, thereby causing a light beam with a specific wavelength to be generated by the energy of the formed excitons. The organic light emitting display does not require a separate light source such as a backlight, and therefore has a low power consumption. Furthermore, since a wide viewing angle and a fast response time can be easily ensured, the organic light emitting display is promising as a next generation display.
In terms of a driving method, organic light emitting displays are classified into a passive matrix type and an active matrix type. In recent years, the active matrix type has become more popular than the passive matrix type because of advantages in low power consumption, high definition, fast response time, wide viewing angle, and thinness and lightness.
In such an active matrix type organic light emitting display, a pixel region is formed on a substrate so as to display an actual image, and pixels, each of which is a basic unit of an image, are arranged in a matrix form. An organic light emitting diode is disposed for each pixel. The organic light emitting diode is constructed such that a first pixel electrode (anode) and a second pixel electrode (cathode) are sequentially formed with an emitting layer including a red (R), green (G), or blue (B) organic material interposed therebetween. A thin film transistor (TFT) is in contact with the organic light emitting diode for each pixel so that each pixel can be separately controlled.
A driving voltage of the organic light emitting display depends on the first pixel electrode, the emitting layer, and the second pixel electrode forming the organic light emitting diode. With larger sized organic light emitting displays with higher brightness, the driving voltage as well as power consumption increases. Therefore, an interface of the organic light emitting diode has to be regulated so as to effectively transport electrons and holes.